Here's some info that I got when I asked for help with the same Ipod problem on my bike. Now most of my songs are at the same volume. I still have a few that are low. All following is Cut and paste from previous forum posts.
I always convert all songs that I rip from CDs or any other source to AAC format as well because they take up less room on the Ipod and are adjusted automatically as well. I usually adjust the main volume on my Ipod to about 90% and then control to overall volume of the songs on my bike radio. However, they will still vary some (smaller levels) from song to song as recording quality will still vary from song to song. Hope this helps.
To set iTunes to play songs at the same sound level:
1 In iTunes, choose iTunes > Preferences if you’re using a Mac, or choose
Edit > Preferences if you’re using a Windows PC.
2 Click Playback and select Sound Check, and then click OK.
To set iPod nano to use the iTunes volume settings:
m Choose Settings and set Sound Check to On.
If you haven’t activated Sound Check in iTunes, setting it on iPod nano has no effect
Step by step below:
Edit/preferences/ playback/sound check/ok - exit
Setting Songs to Play at the Same Volume Level (cut and pasted from manual)
iTunes can automatically adjust the volume of songs, so they play at the same relative
volume level. You can set iPod nano to use the iTunes volume settings.
To set iTunes to play songs at the same sound level:
1 In iTunes, choose iTunes > Preferences if you’re using a Mac, or choose
Edit > Preferences if you’re using a Windows PC.
2 Click Playback and select Sound Check, and then click OK.
To set iPod nano to use the iTunes volume settings:
m Choose Settings and set Sound Check to On.
If you haven’t activated Sound Check in iTunes, setting it on iPod nano has no effect.